Restarts¶

The main results of a BAND calculation are stored in the rkf file. If you save this file you can use it to restart your calculation. The input for the restart calculation is essentially the same, except for some extra keys, like Restart, Grid, and DensityPlot.

Plots of the density (and many other symmetric properties) can can be obtained with the key DensityPlot. Density and orbital plot restarts require the specification of the Grid key. With the subkey SCF you can start the SCF procedure with the last solution from the restart file. This can be useful if the SCF did not converge or if you want to compute some post-SCF properties (e.g. the DOS or the band structure). Similarly, a geometry optimization can be restarted with the subkey GeometryOptimization You can use the geometry of a previous calculation.

Usually the input for a restarted job is the same as for the original calculation, with some extra options, described in this section.

Some examples are available in the \$ADFHOME/examples/band directory and are discussed in the Examples section.

Restart key¶

Restart
File string
SCF [True | False]
DensityPlot [True | False]
OrbitalPlot [True | False]
NOCVdRhoPlot [True | False]
NOCVOrbitalPlot [True | False]
UseDensityMatrix [True | False]
End

Restart
Type: Block Tells the program that it should restart with the restart file, and what to restart.
File
Type: String Name of the restart file.
SCF
Type: Bool False Restart the SCF procedure.
DensityPlot
Type: Bool False Goes together with the DensityPlot block and Grid blocks
OrbitalPlot
Type: Bool False Goes together with the OrbitalPlot and Grid
NOCVdRhoPlot
Type: Bool False Goes together with the NOCVdRhoPlot and Grid blocks.
NOCVOrbitalPlot
Type: Bool False Goes together with the NOCVOrbitalPlot and Grid blocks.
UseDensityMatrix
Type: Bool False If set to True: For restarting the SCF the density matrix will be used. Requires you to set ‘Save DensityMatrix’ in the previous run.

Grid¶

The Grid block is used for restart options OrbitalPlot, DensityPlot, NOCVOrbitalPlot and NOCVdRhoPlot. There are two ways to define your grid. The most easy way is to use the Type key, which automatically generates a grid around the atoms in the unit cell:

Grid
Type [coarse | medium | fine]
End

Grid
Type: Block Options for the regular grid used for plotting (e.g. density plot). Used ICW the restart option.
Type
Type: Multiple Choice coarse [coarse, medium, fine] The default regular grids.

One alternative is to specify everything by hand via the ‘UserDefined’ sub-block.

Grid
UserDefined # Non-standard block. See details.
...
End
End

Grid
Type: Block Options for the regular grid used for plotting (e.g. density plot). Used ICW the restart option.
UserDefined
Type: Non-standard block Once can define the regular grid specification in this block. See example.

The following input would create a cube from (-1,-1,-1) to (1,1,1):

Grid
UserDefined
-1 -1 -1 ! Starting point
1 0 0 0.1   ! vec1 and dvec1
0 1 0 0.1   ! vec2 and dvec2
0 0 1 0.1   ! vec3 and dvec3
20 20 20    ! nr. of steps along three directions
End
End


One can also specify a text file from which the grid is imported:

Grid
FileName string
End

Grid
Type: Block Options for the regular grid used for plotting (e.g. density plot). Used ICW the restart option.
FileName
Type: String Read in the grid from a file. The file format of the grid is: three numbers per line (defining the x, y and z coordinates of the points).

Plots of the density, potential, and many more properties¶

DensityPlot # Non-standard block. See details.
...
End

DensityPlot
Type: Non-standard block Plots of the density. Goes together with the Restart%DensityPlot and Grid keys.

The DensityPlot block goes together with the Restart%DensityPlot and Grid keys. Example input:

...
Restart
File my_file.rkf
DensityPlot
End

Grid
Type Coarse
End

DensityPlot
rho(fit)
vxc[rho]
End
...


After such a run you get a TAPE41 file that you should rename to my.t41, and view with ADFview.

The most common properties to plot are:

• rho(fit) The fitted density.
• v(coulomb) The Coulomb potential.
• vxc[rho(fit)] the XC potential (using the fitted density)
• vxc[rho] XC potential of the exact density
• rho The density
• |gradRho| The norm of the gradient of the density
• tau The symmetric kinetic energy density
• LDOS The local density of states. (See LDOS key)
• elf[rho] The electron localization function

Some more specialized options are:

• rho(deformation/fit) the fitted deformation density
• rho(atoms) The density of the startup atoms
• v(coulomb/atoms) The Coulomb potential of the start density
• s[rho] Reduced density gradient. Common ingredient for XC functionals
• s[rho(fit)] Same as above, now for the fit density
• alpha[rho] Ingredient for some meta-GGAs

In the BAND example directory there is the Frags_COCu example which shows how this can be used in combination with the Fragment key.

Orbital plots¶

OrbitalPlot # Non-standard block. See details.
...
End

OrbitalPlot
Type: Non-standard block Goes together with the Restart%OrbitalPlot and Grid keys. See Example.

The OrbitalPlot block goes together with the Restart%OrbitalPlot and Grid keys. Example input:

...
Restart
File my_file.rkf
OrbitalPlot
End

Grid
Type Coarse
End

OrbitalPlot
1 Band 5 8  ! for k-point 1 plot bands 5 to 8
5 Band 6    ! for k-point 5 plot band 6
6 -0.2 +0.3 ! for k-point 6 plot bands between -0.2 and +0.3 a.u. w.r.t Fermi level
End
...


After such a run you get a TAPE41 file that you should rename to my.t41, and view with ADFview.

Induced Density Plots of Response Calculations¶

ResponseInducedDensityPlot # Non-standard block. See details.
...
End

ResponseInducedDensityPlot
Type: Non-standard block Goes together with Restart%ResponseInducedDensityPlot and Grid.

ResponseInducedDensityPlot (block-type) The ResponseInducedDensityPlot block goes together with the Restart%ResponseInducedDensityPlot and Grid keys. In the BAND example directory there is the TD-CDFT for MoS2 Monolayer example that shows how this can be used. Example input:

...
Restart
File my_file.rkf
ResponseInducedDensityPlot
End

Grid
Type Coarse
End

ResponseInducedDensityPlot
XCOMPONENT 5 8  ! plot x component of induced densities
! for frequencies number 5 to 8
YCOMPONENT 6    ! plot y component of induced densities
! for frequency number 6
ZCOMPONENT 1    ! plot z component of induced densities
! for frequency number 1
End
...


After such a run you get a TAPE41 file that you should rename to my.t41, and view with ADFview.

Attention

The plotting capability works only with response calculation RUNKF files based on the NewResponse method!

NOCV Orbital Plots¶

NOCVOrbitalPlot # Non-standard block. See details.
...
End

NOCVOrbitalPlot
Type: Non-standard block Goes together with the Restart%NOCVOrbitalPlot and Grid keys. See example.

The NOCVOrbitalPlot blockg oes together with the Restart%NOCVOrbitalPlot and Grid keys. See example PEDANOCV_MgO+CO. Example input:

...
Restart
File my_file.rkf
NOCVOrbitalPlot
End

Grid
Type Coarse
End

NOCVOrbitalPlot
1 Band 5 8 ! for k-point 1 plot NOCV Orbitals 5 to 8
End
...


After such a run you get a TAPE41 file that you should rename to my.t41, and view with ADFview.

NOCV Deformation Density Plots¶

NOCVdRhoPlot # Non-standard block. See details.
...
End

NOCVdRhoPlot
Type: Non-standard block Goes together with the Restart%NOCVdRhoPlot and Grid keys. See example.

The NOCVdRhoPlot blockg oes together with the Restart%NOCVdRhoPlot and Grid keys. See example PEDANOCV_MgO+CO. Example input:

...
Restart
File my_file.rkf
NOCVdRhoPlot
End

Grid
Type Coarse
End

NOCVdRhoPlot
1 Band 5 8 ! for k-point 1 plot NOCV deformation densities 5 to 8
End
...


After such a run you get a TAPE41 file that you should rename to my.t41, and view with ADFview.

LDOS (STM)¶

LDOS
DeltaNeg float
DeltaPos float
Shift float
End

LDOS
Type: Block Local Density-Of-States information. This can be used to generate STM images in the Tersoff-Hamann approximation (see https://doi.org/10.1103/PhysRevB.31.805)
DeltaNeg
Type: Float 0.0001 Hartree Lower bound energy (Shift-DeltaNeg)
DeltaPos
Type: Float 0.0001 Hartree Upper bound energy (Shift+DeltaPos)
Shift
Type: Float 0.0 Hartree The energy bias with respect to the Fermi level.

The local density of states is integrated over the resulting interval. Example of an LDOS restart:

Restart
File my_file.rkf
DensityPlot
End

Grid
Type Coarse
End

DensityPlot
LDOS
End

LDOS
Shift    0.1
DeltaNeg 0.001
DeltaPos 0.0
End


According to this example, we restart from the result file of a previous calculation. The calculation will generate a file TAPE41 which can be viewed with ADFview. (Rename the file to my.t41)

Save string

Save